“What there was, clearly, was a strong strand of feeling against uncontrolled migration, and I lay the responsibility of that squarely at the door of Prime Minister Blair, who failed to impose a transitional regime in the UK in 2004,” Hammond said.

The European Union admitted 10 new countries as part of a major expansion in 2014. Eight of those countries, the A8, were Eastern European states that were less prosperous than Western and Northern European states, with relatively lower per capita income levels in comparison to the EU average.

The A8 consisted of the Czech Republic, Estonia, Hungary, Latvia, Lithuania, Poland, Slovakia, and Slovenia. Freedom of Movement rights, granted upon entry to the EU, meant migrants from these countries moved in large numbers to the EU’s wealthiest nations.

While the likes of Germany and France managed the transition successfully, Hammond believes that Blair’s government failed to do so. This set into motion a swathe of anti-immigrant sentiment across much of the UK and helped cause the Brexit, Hammond argued.

“So while other countries in Europe smoothly transitioned the A8 members and the freedom of movement from A8 members, Britain took the full force of the tide in 2004, and that created a public perception that we still haven’t shaken off to this day,” he said on a panel that included IMF chief Christine Lagarde, Bank of Japan Governor Haruhiko Kuroda, and German Finance Minister Wolfgang Schauble.

Hammond also rejected suggestions that Brexit was driven by similar sentiments to the election of Donald Trump as US president, saying: “It was absolutely the opposite of the anti-trade rhetoric that we heard in the United States.”

One of the key arguments of Brexiteers, Hammond said, was to “do more trade with the rest of the world. That Britain would be free to make trade agreements beyond Europe.”

“We have been very clear with the 3.2 million EU nationals in the UK that as far as we are concerned they are welcome, … provided we can be assured of a reciprocal right for the 1.2 million UK nationals living in the EU, then we would expect that to be settled,” he said.